The Bosch PRO Stainless Steel and Metal Bonded Cutting Disc uses premium aluminium oxide grains for strength and durability. The grains are combined with functional fillers and embedded in a phenol resin matrix for additional strength. The disc is reinforced with a high-quality fibreglass net to ensure safer and more stable performance. Plus its iron free, this means you don’t need to worry about rust on your workpiece, if you cut stainless steel only.